Unfortunately that's not possible. The "auto" interval works by analyzing the time range that we expect to find data. This is currently done by looking at the timefilter and saying "the time filter covers 10 hours, so we should use a 15 minute interval". The other time fields in your index pattern are not being filtered though, and should represent a totally different time range, so we can't auto bucket.

So with my log data, I add date fields that contain the time when they were shipped, routed to the correct queue within RabbitMQ, and indexed. I want to create a line chart visualization that displays the total # of events and then split lines for the shipped/routed/indexed times.

Would it not be possible to specify 'Auto' interval for the @timestamp field, and have the split line sub-buckets inherit the interval that it defines for itself?